1991 Volume 31 Issue 13 Pages 919-926
Multimodality evoked potentials (EPs) or three types of EPs — auditory brainstem response (ABR), somatosensory evoked potential (SEP), and visual evoked potential (VEP) — were recorded in 51 cases of traumatic intracranial hemorrhage within 3 days after injury. In order to assess these EPs, five EP grades were constructed, from normal, Grade I, to highly abnormal, Grade V. Furthermore, an EP pattern classification was devised to integrate the respective EP grades. Namely, PA, consisting of all three EPs within Grades I-III; PB, composed of one type of EP or both ABR and VEP at Grades IV and V; Pc, consisting of both SEP and VEP at Grades IV and V; PD, comprising both ABR and SEP at Grades IV and V; and PE, covering all three EPs at Grades IV and V. PA signifies “no severe damage, ” PB, “localized damage, ” PC, “severe cerebral damage, ” PD, “severe brainstem damage, ” and PE, “severe diffuse damage.” The results when compared with computed tomography (CT) findings were as follows: 1) The size of hematoma correlated with the SEP grade in 16 cases of acute epidural hematoma; a hematoma diameter of 17.5 mm was the threshold value at which SEP abnormalities developed. Eleven patients who underwent surgical removal of the hematoma showed “no severe damage, ” and the outcome was good. 2) In 13 cases of acute subdural hematoma, six cases revealed “severe cerebral damage” or “severe diffuse damage.” In such cases, the degree of damage was not related to the hematoma size, and the outcome was very poor. 3) In 13 cases of a solitary contusional hemorrhage, only one case revealed “severe diffuse damage” and subsequently died. 4) The CT findings were not in agreement with the EP data in nine cases of diffuse axonal injury, but the degree of EP abnormality correlated with the outcome. All three patients with “severe diffuse damage” died. The determination of the actual state of brain damage by morphological diagnosis with CT alone may be incomplete, and the pathological state can be precisely determined by functional evaluation simultaneously using three types of EPs.
